The present invention generally relates to dentistry and more particularly to oral implantology.
The loss of permanent teeth by a person has resulted in the need for a denture to replace the natural teeth to assist the person in chewing as well as in proper functioning of the remaining natural teeth. Conventional dentures rest on the gingiva or gingival tissue and, where possible, have been anchored to existing natural teeth to maintain the denture in position. In cases where all of the teeth have been extracted from either the upper or lower jaw, or both, a full denture was utilized in direct contact with the gingival tissue at an appropriate time following extraction of the last natural teeth.
Although such dentures proved satisfactory, their ultimate success depended upon a variety of factors including the patient's perseverence and ability to tolerate the discomfort as well as the resulting diminished chewing capacity. Also, since the denture was resting on the gingival tissue, the mandible or maxillary bone resorbed which resulted in shrinkage of the tissue. Such tissue shrinkage, in turn, made it necessary to reline or rebase the denture in order to ensure a proper fit.
One solution to this problem which has been proposed in the field of dentistry involves endosseous and subperiosteal implants. These implants have been attached by a variety of techniques during surgery which include the opening of the gingival tissue followed by the securement of a frame member to the exposed bone. Thereafter, the gingival tissue was sutured and an impression made in the mouth. Dentures then could be custom manufactured for fitting into the patient's mouth by securement of the denture to the implanted frame member.
For example, U.S. Pat. No. 3,514,858 proposed to embed studs or posts into the bone so that a denture can be secured to such post. An improved endossius ramus implant is shown in U.S. Pat. No. 3,641,671. In U.S. Pat. No. 3,748,739, the implanted posts or studs are interconnected by bars for better securing the dentures thereto. U.S. Pat. No. 3,889,375 proposes a one-piece support for upper dentures. U.S. Pat. No. 4,202,099 is another form of a ramus implant. U.S. Pat. No. 4,253,833 relates to a technique for securing the stud or post implant wherein temporary caps are used during surgery, which caps later are replaced by a tooth-receiving head member. U.S. Pat. No. 4,370,134 relates to an upper denture support structure. U.S. Pat. No. 4,511,335 relates again to an improved endossius implant. Finally, U.S. Pat. No. 4,516,937 relates to a lower jaw dental prosthesis which relies on critical lengths and heights of an arcuate metal strip implant.
While all of these techniques have to some degree solved the problem of securing the denture directly in contact with the gingival tissue, improvement in this field of implantology still is required. For example, conventional subperiosteal implants make the suturing step of the surgery difficult since little room between the tissue and the denture securing bar exists. Another problem involves the difficulty in taking the impression due to the presence of the denture securing bar and the space between such bar and the sutured gingival tissue.